The present invention relates to methods for treating waste pickle liquor solutions and, in particular, to methods for treating waste pickle liquor solutions to reduce silica concentrations therein.
In the manufacture of steel, surface scale formed during the rolling process is generally removed by means of a concentrated sulfuric or hydrochloric acid solution known as pickle liquor. The treatment of such waste pickle liquor can pose significant environmental challenges.
One of the materials which generally needs to be removed from waste pickle liquor consists of silica. Heretofore silica has been removed by chemical precipitation, but such chemical precipitation processes may be both expensive and time consuming.
It is, therefore, the object of the present invention to remove suspended and colloidal silica from waste pickle liquor by means of a less expensive physical separation process.